1. Field of the Invention
The present invention relates to an optical fiber cleaver for cleaving an optical fiber so that a cleaved section is formed as a mirror surface.
2. Description of the Related Art
An optical fiber has a tendency that, when a scratch is formed on the outer peripheral surface of an optical fiber from which a sheath or coating was peeled and the scratch is grown by pulling or bending the fiber, the fiber is broken at the scratch at once to obtain mirror end surfaces suitable for connection or splicing. In the past, there have been proposed various cleavers for performing such cleaving, including a cleaver proposed by the Inventors, in which a cleaving operation can be facilitated or undesired scratch(s) is not formed in the cleaved surface and therearound. Examples are shown in FIGS. 6 and 7.
FIG. 6 shows an example of a cleaver in which the cleaving operation is facilitated and is a view of the cleaver, looked at from an optical axis of an optical fiber A. In this cleaver, when the optical fiber A from which a coating was peeled is pinched between upper and lower clamp members B, C and a slider D is directly moved in a direction shown by the arrow a, a blade E mounted on a distal end of the slider D gives a scratch to a lowermost part of the optical fiber A, and then, a cam follower F provided on the slider D lifts an end 1 of a pusher G pivoted around a shaft X, with the result that the other end J of the pusher G is lowered to apply stress to the scratch of the optical fiber A, thereby cleaving the optical fiber A at the scratch. In this case, the slider D is automatically slid by a motor H, and the operation is automatically performed by turning ON a switch.
FIG. 7 is a plan view of a cleaver in which an undesired scratch is not formed in the cleaved surface of an optical fiber. In this cleaver, when the optical fiber A from which a coating was peeled is pinched between supporting clamp members L fixed to a base K and pressing clamp members N fixed to a lid plate M and a slider O is directly moved in a direction shown by the arrow a, a blade P mounted on the slider O gives a scratch to a lowermost part of the optical fiber A, and the slider O is stopped by attracting it to a magnet Q disposed in front of the slider. Then, when a pusher R provided on the lid plate M is lowered, stress is applied to the scratch of the optical fiber A by the pusher R, thereby cleaving the optical fiber A at the scratch. Another magnet Q is disposed behind the slider O so that accidental movement of the slider O is prevented.
Although various optical fiber cleavers have been proposed till now, there are few cleavers in which both operability and functionality are excellent. For example, in the cleaver shown in FIG. 6, since the pusher G for applying the stress to the optical fiber A is pivoted around the shaft X, when a multi fiber ribbon fiber is handled, due to difference in distance from the fulcrum, bending strokes between fibers are differentiated not to attain the uniform bending stress, with the result that the uniform mirror surface may not be obtained. Further, in the cleaver shown in FIG. 7, after the scratch was given to the optical fiber A, the slider O is attracted to the magnet Q to prevent undesired scratch from being given to the optical fiber A. However, since the slider O must be returned to its original starting position before starting a next operation, a magnetic force is relatively small. Thus, the slider O may be returned erroneously to give undesired scratch to the optical fiber A.
According to a first aspect of the present invention, there is provided an optical fiber cleaver comprising a blade movable directly in a direction perpendicular to an optical axis of an optical fiber clamped and capable of giving a scratch to the outer peripheral surface of an optical fiber, and a pusher movable linearly in the direction perpendicular to the optical axis of the optical fiber clamped and for pushing the optical fiber to cleave it at the scratched part and wherein it further comprises a reverse-running prevention mechanism which prevents the blade which was moved directly and gave the scratch to the optical fiber from being directly moved reversely and giving a scratch to the optical fiber again.
According to a second aspect of the present invention, in the optical fiber cleaver, the reverse-running prevention mechanism comprises a cam moved directly in connection with the blade and a cam follower being contacted with the cam and capable of directly moving the pusher, and, after the optical fiber has been scratched by the blade, the cam is locked with the cam follower so as to prevent the cam from being directly moved reversely.
According to a third aspect of the present invention, in the optical fiber cleaver, the reverse-running prevention mechanism comprises a cam moved directly in connection with the blade and a cam follower being contacted with the cam and capable of directly moving the pusher, and the cam presses the pusher automatically against the optical fiber for cleavage after the optical fiber has been scratched by the blade and, after the scratch has been given completely, is locked with the cam follower so as to prevent the cam from being directly moved reversely.
According to a fourth aspect of the present invention, in the optical fiber cleaver, after the optical fiber has been scratched by the blade, the cam lowers the pusher and is capable of maintaining the pusher in a lowered condition thereafter.